Gun blast stripper and diffuser

ABSTRACT

An apparatus for diffusing and directing the energy from a gun blast from aircraft mounted guns including a stripper attached to each said gun, said stripper having a plurality of openings for directing energy from a gun blast in a downward direction, a curved acceleration ramp positioned forward of said guns, and one or more cascades for directing energy downwardly.

United States Patent Bryant et al.

GUN BLAST STRIPPER AND DIFFUSER William W. Bryant, Ferguson; Richard T.Groff, Ladue, both of Mo.

Assignee: The United States of America as represented by the Secretaryof the Navy Inventors:

Filed: Jan. 25, 1971 Appl. No.: 109,405

0.5. CI. ..89/14 C, 89/375 R Int. Cl. ..B64d 7/02, F4lf 17/12 FieldofSearch ..89/l4 R, 14 C, 14 D, 14 SB, 89/37.5 R

[ 51 June 20, 1972 [56] References Cited UNITED STATES PATENTS 2,787,1944/1957 Peterson ..89/14 C Primary Examiner-Stephen C. BentleyAttorney-R. S. Sciascia, et al.

[57] ABSTRACT An apparatus for diffusing and directing the energy from agun blast from aircraft mounted guns including a stripper attached toeach said gun, said stripper having a plurality of openings fordirecting energy from a gun blast in a downward direction, a curvedacceleration ramp positioned forward of said guns, and one or morecascades for directing energy downwardly.

3 Claims, 6 Drawing Figures PATENTED Z I9 2 3.670 622 sum 10F 2 IN VE'NTORTS.

WILL/HM w BRYANT ,4

BY RICHARD T GEOFF W774 644.2 s. we;

AT TORN E Y8 GUN BLAST STRIPPER AND DIFFUSER BACKGROUND OF THE INVENTIONThe present invention relates to an auxiliary device for automaticweapons, such as a machine gun, and more particularly relates to anauxiliary device for preventing damaging shock waves from causing engineflame out and protecting fragile equipment on an aircraft from the shockproduced by firing a weapon, such as a rapid firing cannon.

The use of auxiliary devices attached to or adjacent to gun barrels isquite old in the gun art. For example, the idea that a baffle justoutside the muzzle could be used to provide a thrust to reduce therecoil momentum dates back prior to World War I. These devices which arereferred to as muzzle brakes, have had widespread use, particularlyduring World War II on antitank guns. Heretofore, however, there has notbeen any need to dilfuse or direct a gun blast in any particulardirection. Most present day military aircraft, such as the McDonnellDouglas Corporation Phantom II, has a radome in the forward fuselage anda Gatling type cannon is positioned in the forward fuselage beneath theradar. The repeated shock waves created by firing the weapon can have anadverse efi'ect on the relatively frangible hardware of the radarsystem. Accordingly, it is desirable to reduce as much as possible, thisadverse effect caused by repeated and rapid firing of the weapon.

Also gun installations located forward of jet engine inlet ductsfrequently cause engine operational problems such as compressor stall orengine flame out when the weapon is fired at moderate to high altitudes(35,000 to 50,000 feet and above). The engine problems are related tointerruption of the air flow due to pressure and/or temperature changesto normal air inlet flow of the engine due to muzzle blast efi'ects. Thediffusion and deflection of muzzle blast and residue from engine inletscan improve or prevent the detrimental engine operational effects causedby firing the weapon. The diversion and diffusion of muzzle blast awayfrom the engine air inlet ducts is therefore also a desired result ofany muzzle diffuser located forward of the engine inlets on a highperformance jet aircraft.

SUMMARY OF THE INVENTION The present invention relates to a gun blaststripper and diffuser that is provided on an aircraft for divertinggases from guns attached on the aircraft. A stripper is attached to eachgun barrel and the stripper is provided with a plurality of slots whichdirect energy downwardly. A shroud is placed around each weapon, and anopening is provided in the bottom of the shroud for permitting escape ofthe gases stripped from the guns. An acceleration ramp is positionedforward of the strippers and a fire tube is provided through theacceleration ramp and dome of the shroud to permit passage of thebullets. A pair of strakes are positioned in the shroud opening and oneor more cascades are provided transverse to the strakes in order todirect the gun blast energy downwardly.

it is therefore a general object of the present invention to provide anapparatus for stripping, diffusing and deflecting the gun blast from anaircraft mounted weapon.

Other objects and advantages of the present invention will be readilyappreciated as the same becomes better understood by reference to thefollowing detailed description when considered in connection with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial isometric view ofa forward end of an aircraft showing a gun blast diffuser attachedthereon;

FIG. 2 is a front view of a diffuser showing a dome having a fire tubetherein;

FIG. 3 is an end view, partially broken away, showing gun barrels andstrippers attached thereto;

FIG. 4 is a partial sectional view showing a preferred embodiment of thepresent invention;

FIG. 5 is a bottom view showing strakes and cascades; and FIG. 6 is apartial sectional view showing a stripper attached to a gun barrel.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, aforward end of an aircraft fuselage 11 is shown having a radome 12. Agun 13, such as a multi-barrel machine gun, is mounted to fuselage 11and a shroud 14 surrounds the barrels of gun 13. As shown in FIGS. 1, 2,and 4 of the drawings, shroud 14 has a spherical dome portion 15 on itsforward end and a firing tube 16 is provided through dome portion 15 forproviding an exit for bullets fired from gun l3. Shroud 14 is providedwith a longitudinally extending bottom opening and a pair of strakes 17and 18 are positioned in the opening. A pair of cascades 21 and 22 areattached to strakes l7 and 18 and are slanted to facilitate diffusion ofthe muzzle blast of gun 13. A curved ramp 23 is provided in shroud 14forward of guns l3 and ramp 23 is curved downwardly to deflect themuzzle blast of gun l3 downwardly and over cascades 21 and 22. As bestshown in FIG. 4 of the drawing, firing tube 16 passes through curvedramp 23 and tapered end 24 of tube 16 serves as a pickoff lip to furtherdiffuse the muzzle blast and divert it over cascades 21 and 22.

Referring now to FIGS. 3, 4, and 6 of the drawing, a stripper 25 isprovided on the end of each gun barrel 26. By way of example, gun 13might be a machine gun having six barrels 26 which are rotatable, andgun 13 is designed so that a projectile is fired through the lowestpositioned barrel 26. A plurality of enlarged chambers 27 are providedin each stripper and each chamber is provided with an aperture 28 thatpermit escapage of gases produced by firing gun 13. Forward plate 31 andrear plate 32 are provided for positioning strippers 25 with barrels 26,and apertures 28 in strippers are positioned so, that upon firing of gun13 the gases will pass through the bottom opening of shroud 14.

In operation, a large portion of the gas produced by firing gun 13 isstripped into collection chambers 27 of strippers 25 and guideddownwardly past the aft portion of strakes l7 and 18. Some of theremaining expanding gas is collected and guided downwardly by cascades21 and 22. Curved ramp 23 and pickoff lip 24 also direct the expandinggases downwardly so that only a very small amount of gas exits throughfiring tube 16 with the projectile.

It can thus be seen that the blast hood and diffusion stripper of thepresent invention directs the energy produced by firing the guns awayfrom the inlet ducts of the jet engine and thus eliminates the problemof engine flameout during high altitude and high angle of attack whilefiring the guns.

We claim:

1. A device for deflecting a gun blast from an aircraft mounted gunhaving a plurality of rotatable barrels comprismg:

a hood surrounding said gun, said hood having a longitudinally extendingbottom opening and a curved ramp attached inside said hood forward theend of said gun for deflecting gas through said bottom opening,

a firing tube attached to said hood and extending through said curvedramp for providing a passageway for projectiles fired from said gun, and

a gas stripper attached to each said barrel and having a plurality ofcollection chambers therein, with each said collection chamber having asingle aperture for permitting passage of gas through said bottomopening.

2. A device for deflecting a gun blast from an aircraft mounted gun asset forth in claim 1 having a pair of cascades positioned transverse tosaid longitudinally extending bottom opening.

3. A device for deflecting a gun blast from an aircraft mounted gun asset forth in claim 1 wherein a spherical dome is provided on the forwardend of said hood.

1. A device for deflecting a gun blast from an aircraft mounted gunhaving a plurality of rotatable barrels comprising: a hood surroundingsaid gun, said hood having a longitudinally extending bottom opening anda curved ramp attached inside said hood forward the end of said gun fordeflecting gas through said bottom opening, a firing tube attached tosaid hood and extending through said curved ramp for providing apassageway for projectiles fired from said gun, and a gas stripperAttached to each said barrel and having a plurality of collectionchambers therein, with each said collection chamber having a singleaperture for permitting passage of gas through said bottom opening.
 2. Adevice for deflecting a gun blast from an aircraft mounted gun as setforth in claim 1 having a pair of cascades positioned transverse to saidlongitudinally extending bottom opening.
 3. A device for deflecting agun blast from an aircraft mounted gun as set forth in claim 1 wherein aspherical dome is provided on the forward end of said hood.